Thymus daenensis, a perennial herb, is often grown in areas that experience drought conditions during its growing period. Application of chitosan may compensate for the negative impact of drought stress on the yield o...Thymus daenensis, a perennial herb, is often grown in areas that experience drought conditions during its growing period. Application of chitosan may compensate for the negative impact of drought stress on the yield of oil and secondary metabolites in Thymus.The interactive effects of foliar application of chitosan and drought stress on dry matter,essential oil yield, and selected physiological characteristics including photosynthetic pigments, osmotic adjustment, and lipid peroxidation of Thymus were investigated in a two-year study from 2014 to 2015. Treatments consisted of 0, 200, and 400(iL L'1 chitosan applied to plants grown under field capacity, mild drought stress(50% field capacity), and severe drought stress(25% field capacity). Dry matter yield decreased substantially as drought stress intensified. However, essential oil content increased under stress conditions,with the highest essential oil yield obtained from plants under mild drought stress. Foliar application of chitosan compensated to some extent for dry matter and oil yield reduction of plants grown under drought stress. The highest essential oil yield(1.52 g plant-1) was obtained by application of 400 \iL L_1 chitosan under the mild stress condition in 2015 when plants were mature. The compensatory effect of chitosan in reducing the negative impact of stress conditions on dry matter and oil yield was due mainly to stimulation of osmotic adjustment through proline accumulation and reduction of lipid peroxidase level, which increased the integrity of cell membranes of thyme leaves.展开更多
This study was conducted to evaluate the diurnal effect on essential oil yield and composition of Ledum palustre L. grown in northern Inner Mongolia, China. Essential oil content and composition were determined and co...This study was conducted to evaluate the diurnal effect on essential oil yield and composition of Ledum palustre L. grown in northern Inner Mongolia, China. Essential oil content and composition were determined and compared as a function of different harvesting times viz. 7:00 AM, 11:00 AM, 3:00 PM, 7:00 PM, and 11:00 PM within a day. The essential oil obtained by hydrodistillation was investigated by gas chromatography-mass spectrometry (GC-MS). The yield of essential oil was varied from 1.21% to 1.62%;the maximum oil yield was obtained at 3:00 PM and the minimum at 7:00 PM. Similar to oil yield, qualitative difference in essential oil composition of L. palustre was observed. For the best essential oil yields, L. palustre should be harvested during 11:00 AM to 3:00 PM.展开更多
A comparative study of Cannabis sativa(Hemp)essential constituents obtained by using Supercritical Fluid Extraction(SCFE),Steam Distillation(SD)and Hydrodistillation(HD)is presented here.The optimized extraction tempe...A comparative study of Cannabis sativa(Hemp)essential constituents obtained by using Supercritical Fluid Extraction(SCFE),Steam Distillation(SD)and Hydrodistillation(HD)is presented here.The optimized extraction temperatures were 130,110and 50℃for hydrodistillation,steam distillation and supercritical fluid extraction respectively.The essential oil of C.sativa was analyzed by using Gas chromatography mass spectrometry(GC-MS).A total of 33,30and 31components have been identified in HD,SD and SCFE respectively.Yield of essential oil using SCFE(0.039%)was more than HD(0.025%)and SD(0.035%)extraction respectively.The main component of sesquiterpenes obtained by hydrodistillation at 130℃with their percentages included caryophyllene(40.58%),trans-α-bergamotene(5.41%),humulene(10.97%),cis-β-farnesene(8.53%)and monoterpenes includedα-pinene(2.13%),d-limonene(6.46%),p-cymol(0.65%)and cineole(2.58%)respectively.The main component of sesquiterpenes obtained by SD steam distillation at110℃including caryophyllene(38.60%)trans-α-bergamotene(4.22%),humulene(10.26%),cis-β-farnesene(6.67%)and monoterpenes includedα-pinene(3.21%),d-limonene(7.07%),p-cymol(2.59%)and cineole(3.88%)whereas the more percentages of major components were obtained by SCFE at 50℃included caryophyllene(44.31%),trans-α-bergamotene(6.79%),humulene(11.97%)cis-β-farnesene(9.71%)and monoterpenes includedα-pinene(0.45%),d-limonene(2.13%)p-cymol(0.19%)and cineole(1.38%)respectively.We found yield/efficiency,chemical composition,quality of the essential oils by supercritical fluid extraction superior in terms of modern,green,saving energy and a rapid approach as compared to traditional techniques.展开更多
Theory and concepts of boundary layer mass transfer is applied to correlate experimental data on extraction of essential oils from vegetable leaves and stems, using steam. From these theory, concepts and experimental ...Theory and concepts of boundary layer mass transfer is applied to correlate experimental data on extraction of essential oils from vegetable leaves and stems, using steam. From these theory, concepts and experimental data with seven systems, two correlations are developed to predict the Sherwood number and mass transfer coefficient as function of Reynolds and Schmidt numbers. From these equations, the molar flux, the amount of solute extracted, and the yield of extraction is predicted. A steam of higher temperature normally improves the mass transfer and the yield. A method to estimate the enhancement for temperature increase is proposed. The correlations developed are applied to a case with industrial size that was no part of the data for correlation generation. Theory may be applied for industrial applications.展开更多
This article is investigating the preparation of essential oil from the ether-containing plants of Juniper (</span></span><span style="font-family:Verdana;"><span style="font-family...This article is investigating the preparation of essential oil from the ether-containing plants of Juniper (</span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"><i></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><i><span style="font-family:Verdana;">Juniperus</span></i></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"></i></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">) and spruce (</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"><i></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><i><span style="font-family:Verdana;">Picea</span></i></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"></i></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">) leaves by using the simple water distillation equipment. This water distillation method forms an essential oil with water vapor from plants of Juniper (</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"><i></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><i><span style="font-family:Verdana;">Juniperus</span></i></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"></i></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">) and spruce (</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"><i></span></span></span><span style="font-family:Verdana;"><sp展开更多
基金support from the University of Massachusetts Amherst
文摘Thymus daenensis, a perennial herb, is often grown in areas that experience drought conditions during its growing period. Application of chitosan may compensate for the negative impact of drought stress on the yield of oil and secondary metabolites in Thymus.The interactive effects of foliar application of chitosan and drought stress on dry matter,essential oil yield, and selected physiological characteristics including photosynthetic pigments, osmotic adjustment, and lipid peroxidation of Thymus were investigated in a two-year study from 2014 to 2015. Treatments consisted of 0, 200, and 400(iL L'1 chitosan applied to plants grown under field capacity, mild drought stress(50% field capacity), and severe drought stress(25% field capacity). Dry matter yield decreased substantially as drought stress intensified. However, essential oil content increased under stress conditions,with the highest essential oil yield obtained from plants under mild drought stress. Foliar application of chitosan compensated to some extent for dry matter and oil yield reduction of plants grown under drought stress. The highest essential oil yield(1.52 g plant-1) was obtained by application of 400 \iL L_1 chitosan under the mild stress condition in 2015 when plants were mature. The compensatory effect of chitosan in reducing the negative impact of stress conditions on dry matter and oil yield was due mainly to stimulation of osmotic adjustment through proline accumulation and reduction of lipid peroxidase level, which increased the integrity of cell membranes of thyme leaves.
文摘This study was conducted to evaluate the diurnal effect on essential oil yield and composition of Ledum palustre L. grown in northern Inner Mongolia, China. Essential oil content and composition were determined and compared as a function of different harvesting times viz. 7:00 AM, 11:00 AM, 3:00 PM, 7:00 PM, and 11:00 PM within a day. The essential oil obtained by hydrodistillation was investigated by gas chromatography-mass spectrometry (GC-MS). The yield of essential oil was varied from 1.21% to 1.62%;the maximum oil yield was obtained at 3:00 PM and the minimum at 7:00 PM. Similar to oil yield, qualitative difference in essential oil composition of L. palustre was observed. For the best essential oil yields, L. palustre should be harvested during 11:00 AM to 3:00 PM.
基金University of Agriculture,Faisalabad for research support
文摘A comparative study of Cannabis sativa(Hemp)essential constituents obtained by using Supercritical Fluid Extraction(SCFE),Steam Distillation(SD)and Hydrodistillation(HD)is presented here.The optimized extraction temperatures were 130,110and 50℃for hydrodistillation,steam distillation and supercritical fluid extraction respectively.The essential oil of C.sativa was analyzed by using Gas chromatography mass spectrometry(GC-MS).A total of 33,30and 31components have been identified in HD,SD and SCFE respectively.Yield of essential oil using SCFE(0.039%)was more than HD(0.025%)and SD(0.035%)extraction respectively.The main component of sesquiterpenes obtained by hydrodistillation at 130℃with their percentages included caryophyllene(40.58%),trans-α-bergamotene(5.41%),humulene(10.97%),cis-β-farnesene(8.53%)and monoterpenes includedα-pinene(2.13%),d-limonene(6.46%),p-cymol(0.65%)and cineole(2.58%)respectively.The main component of sesquiterpenes obtained by SD steam distillation at110℃including caryophyllene(38.60%)trans-α-bergamotene(4.22%),humulene(10.26%),cis-β-farnesene(6.67%)and monoterpenes includedα-pinene(3.21%),d-limonene(7.07%),p-cymol(2.59%)and cineole(3.88%)whereas the more percentages of major components were obtained by SCFE at 50℃included caryophyllene(44.31%),trans-α-bergamotene(6.79%),humulene(11.97%)cis-β-farnesene(9.71%)and monoterpenes includedα-pinene(0.45%),d-limonene(2.13%)p-cymol(0.19%)and cineole(1.38%)respectively.We found yield/efficiency,chemical composition,quality of the essential oils by supercritical fluid extraction superior in terms of modern,green,saving energy and a rapid approach as compared to traditional techniques.
文摘Theory and concepts of boundary layer mass transfer is applied to correlate experimental data on extraction of essential oils from vegetable leaves and stems, using steam. From these theory, concepts and experimental data with seven systems, two correlations are developed to predict the Sherwood number and mass transfer coefficient as function of Reynolds and Schmidt numbers. From these equations, the molar flux, the amount of solute extracted, and the yield of extraction is predicted. A steam of higher temperature normally improves the mass transfer and the yield. A method to estimate the enhancement for temperature increase is proposed. The correlations developed are applied to a case with industrial size that was no part of the data for correlation generation. Theory may be applied for industrial applications.
文摘This article is investigating the preparation of essential oil from the ether-containing plants of Juniper (</span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"><i></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><i><span style="font-family:Verdana;">Juniperus</span></i></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"></i></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">) and spruce (</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"><i></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><i><span style="font-family:Verdana;">Picea</span></i></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"></i></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">) leaves by using the simple water distillation equipment. This water distillation method forms an essential oil with water vapor from plants of Juniper (</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"><i></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><i><span style="font-family:Verdana;">Juniperus</span></i></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"></i></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">) and spruce (</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"><i></span></span></span><span style="font-family:Verdana;"><sp
